Liquid crystalline compounds, their production and their use as modifiers for polycarbonates, polyester carbonate and polyesters

ABSTRACT

The present invention relates to aromatic compounds corresponding to formula (I) ##STR1## to their production and to their use as modifiers for thermoplastic aromatic polycarbonates and/or thermoplastic aromatic polyester carbonates and/or thermoplastic aromatic polyesters.

This is a division of application Ser. No. 377,320 filed July 10, 1989,now abandoned.

This invention relates to aromatic compounds corresponding to formula(I) ##STR2## in which --Ar is an aromatic group which may be mononuclearor polynuclear; the polynuclear radical may be attached by one bond oranellated,

R¹ and R² may be the same or different and represent H, chlorine,O--C₁₋₄ -alkyl, --O--C₃₋₆ -cycloalkyl, O--C₆₋₁₄ -aryl, C₁₋₄ -alkyl, C₃₋₆-cycloalkyl, C₆₋₁₄ -aryl, fluorinated C₁₋₄ -alkyl, fluorinated C₃₋₆-cycloalkyl, fluorinated C₆₋₁₄ -aryl or a group corresponding toformulae (I) a) to 1) below: ##STR3## where X again represents thesubstituents from H to fluorinated C₆₋₁₄ -aryl mentioned above for R¹and R² ; --M¹ and --M² may be the same or different and represent groupswith two bonds corresponding to formulae (I.1) to (I.11) ##STR4## andm=0, 1 or 2,

n=1 or 2,

o=1,2 or 3 and

p=0 or 1; where p=0,

R² can only be (Ia), (Ib), (Ic) or (Id), excluding compounds nos. 1, 2and 10 on pages 4 and 6 of the present application.

Preferred groups --Ar-- are the groups (Ar1) to (Ar4) ##STR5##

Preferred substituents R¹ and R² are H, CH₃, OCH₃, cyclohexyl, phenyl,CF₃, OCF₃, fluorinated cyclohexyl and fluorinated phenyl.

Preferred groups -M- are (I.1), (I.2), [I.5), (I.8), (I.9) and (I.11).

Preferred index combinations m, n, o, p and q are

m=0, n=1, o-1, p=0;

m=0, n=1, o=1, p=1;

m=0, n=2, o=1, p=1;

m=n=o=p=1;

m=1, n=1, o=2, p=1;

m=0, n=2, o=1, p=0;

m=1, n=2, o=1, p=1 and

m=1, n=1, o=3, p=1.

The compounds corresponding to formula (I) are distinguished by the factthat, on melting, they pass through a liquid crystalline phase. (Forliquid crystalline compounds and phases, see for example D. Demus, L.Richter, Textures of Liquid Crystals, Verlag Chemie, Weinheim - N.Y.,1978, or H. Kelker, R. Hatz, Handbook of Liquid Crystals, Verlag Chemie,Weinheim, Deerfield 1080).

The following four groups of compounds (I,A) to (I,D) are mentioned asexamples of compounds corresponding to formula (I):

(I,A) liquid crystalline compounds corresponding to formula (I) withthree aromatic partial structures, in which

m=0, n=1, o=1 and p=0,

compounds 1 and 2 already being known from the literature (D. B.Schroeder, J. Org. Chem. 38, 3160 (1973) and J. P. Van Meten, B. H.Klanderman, Mol. Cryst., Liquid Cryst. 1973, Vol. 22, pages 285 et seq.)

    ______________________________________                                         ##STR6##                                                                     No.     R.sup.1   M.sup.1    R.sup.2                                          ______________________________________                                        1       CH.sub.3                                                                                 ##STR7##                                                                                 ##STR8##                                        2       CH.sub.3 O                                                                               ##STR9##                                                                                 ##STR10##                                       3       CH.sub.3 O                                                                               ##STR11##                                                                                ##STR12##                                       4       CH.sub.3                                                                                 ##STR13##                                                                                ##STR14##                                       ______________________________________                                    

(I,B) liquid crystalline compounds corresponding to formula (I) withfour aromatic partial structures, in which m=0, n=1, o=1 and p=0:

    ______________________________________                                         ##STR15##                                                                    No.  R.sup.1          M.sup.1   R.sup.2                                       ______________________________________                                              ##STR16##                                                                                      ##STR17##                                                                               ##STR18##                                    5    X.sup.1H                   X.sup.2H                                      6    CH.sub.3                   CH.sub.3                                      7    OCH.sub.3                  OCH.sub.3                                     8    CF.sub.3                   CF.sub.3                                      9    Cl                         Cl                                            ______________________________________                                    

(I,C) liquid crystalline compounds corresponding to formula (I) withfive aromatic partial structures, in which m=n =o=p=1.

Compound 10 has already been mentioned in the literature, cf. V. N.Tsvetkov, Eur, Polym. J. Vol. 21 no. 11, page 933 (1985).

    __________________________________________________________________________     ##STR19##                                                                    No.    R.sup.1                                                                             M.sup.1 M.sup.2 R.sup.2                                                                             Ar                                         __________________________________________________________________________    10     H                                                                                    ##STR20##                                                                             ##STR21##                                                                            H                                                                                    ##STR22##                                 11     CH.sub.3                                                                             "       "      CH.sub.3                                                                             "                                         12     OCH.sub.3                                                                            "       "      OCH.sub.3                                                                            "                                         13     H                                                                                    ##STR23##                                                                             ##STR24##                                                                            H      "                                         14     CH.sub.3                                                                             "       "      CH.sub.3                                                                             "                                         15     OCH.sub.3                                                                            "       "      OCH.sub.3                                                                            "                                         __________________________________________________________________________

(I,D) liquid crystalline compounds corresponding to formula (I) withseven aromatic partial structures, in which m=n=o=p=1:

    __________________________________________________________________________     ##STR25##                                                                    No.                                                                              R.sup.1       M.sup.1                                                                             Ar      M.sup.2                                                                             R.sup.2                                  __________________________________________________________________________    16                                                                                ##STR26##                                                                                   ##STR27##                                                                           ##STR28##                                                                             ##STR29##                                                                           ##STR30##                               17                                                                                ##STR31##                                                                                   ##STR32##                                                                           ##STR33##                                                                             ##STR34##                                                                           ##STR35##                               18                                                                                ##STR36##                                                                                   ##STR37##                                                                           ##STR38##                                                                             ##STR39##                                                                           ##STR40##                               19                                                                                ##STR41##                                                                                   ##STR42##                                                                           ##STR43##                                                                             ##STR44##                                                                           ##STR45##                               __________________________________________________________________________

Preferred compounds corresponding to formula (I) are those which containfrom 3 to 15 aromatic partial structures, the group --Ar-- beingselected as one partial structure irrespective of whether it ismononuclear or polynuclear. Particularly preferred compoundscorresponding to formula (I) are those which contain from 3 to 11aromatic partial structures, the group --Ar-- again being selected asone aromatic partial structure irrespective of whether it is mononuclearor polynuclear. Especially preferred compounds corresponding to formula(I) are those which contain from 3 to 7 aromatic partial structures asdefined above.

In purely formal terms, the compounds corresponding to formula (I) maybe produced from the following structural elements (II) to (VIII):##STR46##

In formulae (II) and (VII), M¹, M² and Ar are as defined for formula (I)and R¹ and R² are also as defined for formula (I), although R¹ and R²may additionally have the function of a readily movable protective groupsuch as, for example, ##STR47## Y and Z are reactive residues ofaromatic carboxylic acid derivatives, for example Cl, Br or anhydridegroups. Reactive in this context means the ability of the carboxylicacid derivatives to form esters with phenols or phenolates.

In addition to the defined function of a reactive residue in theproduction of intermediate stages, Y may also be a readily removableprotective group, for example ##STR48##

In more specific terms, the compounds of formula (I) according to theinvention are prepared by reaction of the phenolic compounds (II) and/or(III) and/or (IV) or alkali salts thereof with the reactive derivativesof aromatic carboxylic acids (V) and/or (VI) and/or (VII); theseesterification reactions may be carried out by known methods, forexample in accordance with Houben-Weyl, Methoden der organischem Chemie,Supplementary Volume E5.

This esterification reaction is preferably carried out in a basicmedium, suitable bases being in particular alkali metal hydroxides, suchas sodium or pctassium hydroxide, alkali metal carbonates or hydrogencarbonates, such as sodium carbonate, sodium hydrogen carbonate,potassium carbonate or potassium hydrogen carbonate, alkali metalacetates, such as sodium or pctassium acetate, alkali metal hydroxides,such as calcium hydroxide, or organic bases, such as triethylamine,diisopropyl ettylamine, 1,8-bis-(dimethylamino)-naphthalene, pyridine,lutidine, collidine, quinoline or N,N-dimethylaniline.

The esterifications are advantageously carried out in the presence of aninert solvent. Particularly suitable inert solvents are ethers, such asdiethylether, di-n-butylether, tetrahydrofuran, dioxane or anisole;ketones, such as acetone, butanone, 3-pentanone or cyclohexanone;amides, such as dimethylformamide or hexamethylphosphoric acid triamide;hydrocarbons, such as benzene, toluene or xylene; halogenatedhydrocarbons, such as carbon tetrachloride or tetrachloroethylene; andsulfoxides, such as dimethylsulfoxide or sulfolan. An excess of theorganic base used, for example pyridine, quinoline, N,N-dimethylanilineor triethylamine, may also occasionally be used as solvent for theesterification. In principle, the esterification reactions according tothe invention may also be carried out in the absence of the auxiliarybase, for example simply by heating the components in an inert solvent.

The reaction temperature is normally in the range from -50° C. to +200°C. and preferably in the range from -20° C. to 160° C. At thesetemperatures, the esterification reactions are generally over after 15minutes to 48 hours.

Accordingly, the present invention also relates to a process for theproduction of the compounds corresponding formula (I) which ischaracterized in that phenolic compounds corresponding to formulae (II)and/or (III) and/or (IV) or alkali salts thereof are esterified by knowprocesses with reactive derivatives cf aromatic carboxylic acidscorresponding to formulae (V) and/or (VI) and/or (VII) in dependenceupon the functionality of the reactants (II) to (VII), taking intoaccount the protective groups to be used, and in dependence upon thevalues to be obtained for the indices "m", "n", "o" and "p" in formula(I).

In one preferred embodiment of the process according to the invention,the phenolic compounds are suspended in an organic solvent, for examplein diethylether, dioxane, tetrahydrofuran or CH₂ Cl₂, with an equimolarquantity of organic base, for example triethylamine, pyridine orN,N-dimethylaniline, and the corresponding aromatic carboxylic acidhalide, preferably the corresponding aromatic carboxylic acid chloride,is added dropwise with stirring in the calculated quantities to theresulting suspension at temperatures in the range from -10° C. to +10°C. The reaction mixture is then stirred for about 10 to 16 hours ataround 20° C., the organic solvent is removed in vacuo and, to separatethe hydrohalides of the organic bases, the residue is taken up in water,the product is filtered under suction and then washed with water until aneutral reaction is obtained.

In another variant of the process according to the invention, thephenolic compounds are dissolved in equimolar quantities of 10% aqueousNaOH or KOH solution, the corresponding aromatic carboxylic acid halideis added with cooling in the calculated quantities, the reaction productprecipitated is filtered off under suction, washed with water untilneutral and dried.

The phenolic compounds corresponding to formula (II) are either knownfrom the literature (see for example J. B. Schroeder, J. Org. Chem. 383160 (1973) and J. P. von Meter, B. H. Klandermann, Mol. Cryst. LiquidCryst. 1973, 22, 285) or may be obtained by known methods, for exampleas follows: ##STR49##

These direct esterification reactions are carried out in a solventsuitable as water entraining agent using acidic catalysts by methodsknown from the literature (cf. for example Houben-Weyl, Methoden derorganischen Chemic, Supplementary Volume E5). Suitable solvents are, forexample, toluene, xylene, chlorobenzene, dichlorobenzene. ##STR50##

Production methods are described, for example, by M. Ueda in J. Org.Chem. 50, 760.

In special cases, it is advisable to block the phenolic OH group by aprotective group.

Suitable methods for carrying out both the amideforming reaction andalso the blocking of phenolic OH groups are described in the literature,for example in Houben-Weyl, Methoden der organischen Chemic, or W. R.Krigbaum in Euro. Polym. J. Vol. 20, 225 (1984).

The reaction of isocyanates and carboxylic acids is also known and isdescribed in Houben-Weyl, Methoden der organischen Chemic E5. ##STR51##

The synthesis of amines by condensation of amides with aldehydes isknown from the literature and is described in Houben-Weyl, Methoden derorganischen Chemie and in H. Ringsdorf, Makromol. Chem. 30, 36.

Compound (VI) is prepared by direct esterification of p-hydroxybenzoicacid with hydroquinone in accordance with DE-OS 3 622 611.

The reactive derivatives of the aromatic carboxylic acids (V) areprepared as follows: ##STR52##

Another synthesis route comprises 1) elimination of the protective groupR by hydrogenation or thermolysis and 2) conversion of the free carboxylgroup into a reactive form ##STR53## by methods known from theliterature. ##STR54##

The other synthesis route corresponds to that for compound (Va).

R has the same meaning as in (Va). In addition, the production of (Vb)is described in O. Exner, Coll. Czeeh. Chem. Commun., 1970, 1371.##STR55##

R has the same meaning as in (Va). The other synthesis route correspondsto that for compound (Va).

The reactive derivatives of the aromatic dicarboxylic acids (VI) andaromatic carboxylic acids (VII) are known from the literature and areprepared by known reactions. Reactive carboxylic acid derivatives (VII)containing protective groups, for example 4-carbobenzoxybenzoic acidderivatives, are prepared in accordance with W. R. Krigbaum, Euro.Polym. J. 20, 225 (1984).

The production of the liquid crystalline compounds according to theinvention from the basic structural elements (II), (III), (IV), (V),(VI), (VII) and other auxiliaries is outlined briefly in the following.

3-Nuclear compounds (m=0, n=1, o=1, p=0) ##STR56## are prepared fromphenols of type (II) or (III) by esterification with reactive aromaticcarboxylic acids.

4-Nuclear compound: is obtained by esterification of the ester biphenol(IV) with 2 mol of a reactive aromatic carboxylic acid derivative:##STR57## (m=o, n=1, o=1, p=o) or from the phenols (II) or (III) byesterification with the reactive carboxylic acid derivative (V)##STR58## (m=o, n=1, o=1, p=1)

5-nuclear compounds (m=1, n=1, o=1, p=1) are obtained by esterificationof the phenols (II) and (III) with reactive aromatic dicarboxylic acids:##STR59##

6-nuclear compounds (m=0, n=1, o=1, p=1): are obtained from 4-nuclearcompounds of the following type: ##STR60## by the synthesis sequence 1.hydrogenation (elimination of the protective group with release of thebisphenol) and 2. esterification of the two phenolic OH groups with anaromatic carboxylic acid derivative (VII) ##STR61##

7-nuclear compounds (m=n=o=p=1): may be obtained from 3-nuclearcompounds, in which R¹,2 =X, ##STR62## and the ring substituent R² is aprotective group of the type ##STR63## by the following synthesissequence: 1) removal of the protective group by hydrogenation (releaseof the phenolic OH function)

2) reaction with a reactive aromatic dicarboxylic acid derivative (VI)##STR64## 7-Nuclear compounds may be obtained from 5- nuclear compounds,in which R^(1/2) represents the protective group ##STR65## by the samesynthesis sequence: 1) removal of the protective group by hydrogenationand

2) reaction of the phenolic OH group with a reactive aromatic carboxylicacid derivative (VII): ##STR66##

8-nuclear compounds (m=0, n=2, o=1, p=1) are obtained from 4-nuclearcompounds of the type ##STR67## mit R¹,2 und ##STR68## by the followingsynthesis sequence: 1) removal of the protective group by hydrogenation

2) reaction of the phenolic OH group with reactive carboxylic acidderivatives corresponding to formula (V) ##STR69##

9-nuclear compounds (m=1, n=1, o=2, p=1) are obtained by consequentutilization of the protective group technique via the followingsynthesis sequence. Esterification of phenols of type (II) or (III), inwhich R¹ or R² is a protective group: ##STR70## After elimination of theprotective group by hydrogenation, bisphenol is esterified together witha 3-nuclear phenol ##STR71## (prepared by removal of the protectivegroup R^(1/2) : ##STR72## and another reactive aromatic dicarboxylicacid derivative (VI) to form the corresponding 9-nuclear compound:##STR73##

Correspondingly higher-nuclear compounds containing more than 9 aromaticring systems may be analogously synthesized.

The compounds corresponding to formula (I), including compounds 1, 2 and10, are suitable as additives for thermoplastic, aromaticpolycarbonates, for thermoplastic polycarbonates, for thermoplastic,aromatic polyester carbonates and for thermoplastic, aromaticpolyesters, producing both an improvement in the rigidity and flexuralstrength of these thermoplastics and also an improvement in theirprocessibility. No such use is either mentioned or even suggested in theliterature references which describe compounds 1, 2 and 10.

The effect of the compounds corresponding to formula (I) is surprisinginsofar as it is known from JA 51 071 346 that aromatic esters havingthe following structure ##STR74## in which Ar is an aromatic groupoptionally substituted by halogen, C₁₋₁₀ alkyl or aralkyl,

may be used as plasticizers for aromatic polycarbonates in quantities offrom 0.01 to 10% by weight.

The addition of liquid crystalline polymers to thermoplastics is known(cf. for example EP-OS 0 030 417). However, a disadvantage is in generalthe limited compatibility of the thermoplastics with liquid crystallinepolymers, the transparency of the thermoplastics above all beingimpaired or totally eliminated.

Infusible, whisker-like poly-(p-oxybenzoate) crystals are described as areinforcing component in U.S. Pat. No. 4,673,724. On account of theirvery high melting or softening points, however, these crystals are verydifficult to produce and are particularly incompatible with otherpolymers.

An improvement in the compatibility between the liquid crystalline phaseand the thermoplastic matrix is described in EP 0 071 968 for partiallycrystalline polymers, such as polyalkylene terephthalate, the bettercompatibility of the phases being achieved by using only oligomers basedon terephthalic acid, 2,6-naphthalene dicarboxylic acid and diphenols,such as 3,3',5,5'-tetramethyl-4,4'-dihydroxydiphenyl, and trimethylhydroquinone having molecular weights of from 2,000 to 10,000 as theliquid crystalline components. Commensurate with the low molecularweights of the liquid crystalline components, the reinforcing effectsobtained are only moderate. Thus, although the elasticity modulus ofpolyethylene terephthalate fibers is increased, their tensile strengthis reduced.

Mixtures of liquid crystalline polymers and amorphous thermoplasticsproduced in situ are also known (cf. for example G. Kiss, PolymerEngineering & Science, 27, pages 410-423 (1987). Mixtures such as theseare attended by the disadvantage that the reinforcing effects obtainabledepend largely upon the mixing conditions and the processing conditionsare often difficult to reproduce.

In addition, in the production of composites of the type in question,the mixing components differ greatly in their melt viscosities underprocessing conditions, so that only a limited number of suitablepolymers is available for the production of the composites.

Chemically reactive, liquid crystalline, aromatic esters which condenseinto the polymer chain through transesterification at a relatively hightemperature have been described as processing aids for conventionalthermoplastices such as aromatic polyesters, or liquid crystallinepolymers which are difficult to process as thermoplastics. However, theincorporation of the aromatic, liquid crystalline esters in the polymerchain leads to a chemical change in the thermoplastics. The disadvantageof this is that, depending on the processing conditions, differentincorporation ratios and, hence, non-reproducible properties areobtained.

Liquid crystalline compounds are described in EP-OS 0 256 470 (Le A 24738-EP) as chain-extending agents for the production of polyurethanes.

The quantities of compounds corresponding to formula (I) for modifyingthe thermoplastic aromatic polycarbonates, the thermoplastic aromaticpolyester carbonates and the thermoplastic aromatic polyesters amount tobetween 0.1% by weight and 30% by weight, preferably to between 0.5% byweight and 25% by weight and more preferably to between 1% by weight and15% by weight, based in each case on the total weight of compoundscorresponding to formula (I) and thermoplastic polycarbonate,thermoplastic polyester carbonate and thermoplastic polyester.

Accordingly, the present invention also relates to the use of thecompounds corresponding to formula (I) for modifying thermoplasticaromatic polycarbonates and/or thermoplastic aromatic polyestercarbonates and/or thermoplastic aromatic polyesters.

Thermoplastic aromatic polycarbonates in the context of the presentinvention are the polycondensates obtainable by reaction of diphenols,particularly dihydroxydiarylalkanes, with phosgene or diesters ofcarbonic acid; in addition to the unsubstituted dihydroxydiarylalkares,those of which the aryl groups bear methyl groups or halogen atoms inthe o- and/or m-position to the hydroxyl group are also suitable.Branched polycarbonates are also suitable. Monophenols for example areused as chain terminators while trisphenols or tetraphenols for exampleare used as branching agents.

The polycarbonates have average weight average molecular weights Mw offrom 10,000 to 300,000, preferably from 150,000 to 250,000 on the onehand and from 20,000 to 40,000 on the other hand, as determined by gelpermeation chromatography or by measurement of the relative viscosity inCH₂ Cl₂ at 25° C. and at a concentration of 0.5 g per 100 ml.

Suitable diphenols are, for example, hydroquinone; resorcinol;4,4'-dihydroxydiphenyl; bis-(hydroxyphenyl)alkanes, such as for exampleC₁₋₈ alkylene or C₂₋₈ alkylidene bisphenols;bis-(hydroxyphenyl)-cycloalkanes, such as for example C₅₋₁₅cycloalkylene or C₅₋₁₅ cycloalkylidene bisphenols;bis-(hydroxyphenyl)-sulfides, ethers, ketones, sulfoxides or sulfones;also α,α'-bis-(hydroxyphenyl)-di-isopropylbenzene and the correspondingnucleus-alkylated or nucleus-halogenated compounds.

Preferred polycarbonates are those based onbis-(4-hydroxyphenyl)-2,2-propane (bisphenol A),bis-(4-hydroxy-3,5-dichlorophenyl)-2,2-propane (tetrachlorobisphenol A),bis-(4-hydroxy-3,5-dibromophenyl)-2,2-propane (tetrabromobisphenol A),bis-(4-hydroxy-3,5-dimethylphenyl)-2,2-propane (tetramethylbisphenol A),bis-(4-hydroxyphenyl)-1,1-cycloyhexane (bisphenol Z) and on trinuclearbisphenols, such as α,α'-bis-(4-hydroxyphenyl)-p-diisopropylbenzene.Other suitable diphenols and the production of the polycarbonates aredescribed, for example, in U.S. Pat. Nos. 3,028,365; 3,062,781 and3,879,347.

Branched polycarbonates are described, for example, in U.S. Pat. No.4,185,009 and in DE-PS 2 500 092.

Thermoplastic aromatic polyesters in the context of the presentinvention are those based on diphenols, aromatic dicarboxylic aciddichlorides, chain terminators and, optionally, branching agents.

Suitable diphenols are the compounds mentioned above for the productionof the polycarbonates.

Monophenols are used as chain terminators while trisphenols andtetraphenols are used as branching agents.

In addition, aromatic tricarboxylic acid trichlorides or aromatictetracarboxylic acid tetrachlorides or acid chlorides of even higheraromatic carboxylic acids may also be used with advantage as branchingagents.

They are used in quantities of from 0.01 to 1 mol-%, based on thearomatic dicarboxylic acid dichlorides used, whereas phenolic branchingagents are used in quantities of from 0.01 to 1 mol-%, based on thediphenols used for the production of the aromatic polyester.

Branching agents for the production of aromatic polyesters aredescribed, for example, in DE-OS 2 940 024, pages 9/10 (Le A 19 932).

Suitable aromatic dicarboxylic acid dichlorides are terephthalic aciddichloride, isophthalic acid dichloride, o-phthalic acid dichloride,diphenyldicarboxylic acid dichloride, diphenylether dicarboxylic aciddichloride, naphthalene dicarboxylic acid dichloride and mixturesthereof.

Preferred mixtures are those of terephthalic acid dichlorides withisophthalic dichlorides in a ratio of from 20:1 to 1:20 and moreespecially in a ratio of 7:3 to 3:7.

The production of the aromatic polyesters from acid chlorides,diphenols, chain terminators and, optionally, branching agents ispreferably carried out in known manner by interfacial polycondensation(cf. for example DE-OS 2 940 024).

Thermoplastic aromatic polyester carbonates in the context of thepresent invention are those obtainable in known manner from diphenols,phosgene, aromatic dicarboxylic acid dichlorides, chain terminators and,optionally, branching agents.

Polyester carbonates and their production are known (cf. for exampleEP-OS 0 036 080, U.S. Pat. No. 3,169,121 and DE-OS 2 714 544).

Suitable diphenols are those already mentioned for the production of thepolycarbonates.

Suitable aromatic dicarboxylic acid dichlorides are those alreadymentioned for the production of the aromatic polyesters, mixtures ofterephthalic acid dichlorides with isophthalic acid dichlorides in themixing ratios already mentioned again being particularly suitable.

Suitable chain terminators are the monophenols used for the productionof the polycarbonates and polyesters.

Suitable branching agents are the more than dihydric phenols and morethan difunctional aromatic carboxylic acid chlorides mentioned above inregard to the aromatic polyesters.

The aromatic polyester carbonates in the context of the inventioncontain up to about 80 mol-% and preferably up to about 50 mol-%carbonate groups, based on the total mols carbonate groups and aromaticcarboxylic acid ester groups.

Both the ester component and the carbonate component of the aromaticpolyester carbonates according to the invention may be present in thepolycondensate in the form of blocks or in statistical distribution.

The relative solution viscosity (η_(rel)) of the aromatic polyesters andpolyester carbonates is in the range from 1.18 to 1.4 and preferably inthe range from 1.22 to 1.3 (as measured on solutions of 0.5 g polyestercarbonate in 100 ml CH₂ Cl₂ solution at 25° C.).

The compounds corresponding to formula (I) are preferably incorporatedin the solution of the polycarbonates or polyester carbonates orpolyesters which is formed in the production of the polycarbonates orpolyester carbonates or polyesters by the interfacial process or whichmay readily be prepared from granulates of these plastics usingconvential solvents. The solutions may then be worked up in knownmanner, for example in evaporation extruders, and the modifiedthermoplastics may be isolated in known manner, for example in granulateform. The solutions may also be directly cast to form films.

The compounds corresponding to formula (I) may also be incorporated in amelt of the polycarbonates or polyester carbonates or polyesters, forexample using extruders, preferably twin-screw extruders; the modifiedthermoplastics may again be isolated in known manner, for example asgranulate.

Accordingly, the present invention also relates to a process for theincorporation of compounds corresponding to formula (I) in thermoplasticaromatic polycarbonates and/or thermoplastic aromatic polyestercarbonates and/or thermoplastic aromatic polyesters, characterized inthat the compounds corresponding to formula (I) are added in quantitiesof from 0.1% by weight to 30% by weight, preferably in quantities offrom 0.5% by weight to 25% by weight and more preferably in quantitiesof from 1% by weight to 15% by weight to solutions of thermoplastic:,aromatic polycarbonates and/or thermoplastic aromatic polyestercarbonates and/or thermoplastic aromatic polyesters in the solventstypically used for these thermoplastics and the resulting solutions aresubsequently worked up in known manner or the compounds corresponding toformula I are incorporated in the quantities mentioned above in melts ofthe polycarbonates and/or polyester carbonates and/or polyesters and themodified thermoplastics are isolated in known manner.

The present invention also relates to thermoplastic aromaticpolycarbonates and/or aromatic polyester carbonates and/or aromaticpolyesters, characterized in that they contain the compoundscorresponding to formula (I) in quantities of from 0.1% by weight to 30%by weight, preferably in quantities of from 0.5% by weight to 25% byweight and more preferably in quantities of from 1% by weight to 15% byweight.

The polycarbonates, polyester carbonates and polyesters modified by theaddition in accordance with the invention of the compounds correspondingto formula (I) combine the advantageous properties already mentionedwith a high degree of transparency, particularly in cases wherecompounds of formula (I) containing 3 to 5 aromatic partial structures(--Ar-- again counting as an aromatic partial structure) are used.

The polycarbonates, polyester carbonates and polyesters modified inaccordance with the invention by the addition of the compoundscorresponding to formula (I) may also contain the usual stabilizerssuitable for the thermoplastics mentioned in the quantities normallyused for these thermoplastics.

The polycarbonates, polyester carbonates and polyesters modified inaccordance with the invention by the addition of the compoundscorresponding to formula (I) are suitable for the production of moldingsby injection molding and extrusion, preferably for applicationsrequiring high rigidity, high dimensional stability ant high surfacequality.

One particularly preferred application of the transparent moldingcompounds according to the invention is in the production of moldingsfor recording acoustic and/or optical information (for example compactdiscs).

EXAMPLES

A) Production of 4-hydroxyphenyl-4-hydroxybenzoate (intermediate stagefor the production of compounds corresponding to formula (I)).

A)a) Produced from 4-hydroxybenzoic acid with introduction of thecarbobenzoxy group as a protective group and esterification withhydroquinone by the Schotten-Baumann method, followed by elimination ofthe protective group. Melting point: 245°-246° C. (cf. W. R. Krigbaum,Eur. Polym. J. 20, page 225 (1984)).

A)b) Direct esterification in accordance with DE-OS 3 622 611. 138.1 gp-hydroxybenzoic acid and 110.1 g hydroquinone are suspended with 2 gboric acid and 2.5 g sulfuric acid in 900 ml xylene and the resultingsuspension is heated under reflux until the elimination of water iscomplete. The product is filtered under suction, dried and washed withdilute sodium bicarbonate solution, redried and dissolved in 100 mlacetone. The product is then filtered off while still hot fromundissolved constituents and precipitated from water, filtered undersuction and dried. Yield: 182 g. Melting point: 245°-247° C.

EXAMPLE 1 1-(4-methoxybenzyloxy)-4-(4-methylbenzoyloxy)-benzene##STR75## 1a) Preparation of 4-methoxybenzoic acid-4-hydroxyphenyl ester

912 g p-methoxybenzoic acid and 660 g hydroquinone are heated underreflux in the presence of 12 g boric acid and ml sulfuric acid (98%)until the elimination of water is over. After cooling, the crystalsprecipitating are filtered under suction, washed and redried. Yield:1250 g colorless crystals. Melting point: 162°-165° C. Mp. J. Org. Chem.37, 1425 (1972) 156° C.

1b) 122.1 g of this product are suspended with 43.5 g distilled pyridinein 500 absolute methylene chloride and 76.8 g p-methylbenzoic acidchloride added to the resulting suspension while cooling with ice. Thereaction mixture is stirred for 14 h at room temperature and dilutedwith 500 ml methylene chloride. The reaction mixture is washed twicewith 200 ml cold 5% hydrochloric acid and twice with 300 ml water. Theorganic phase is dried over sodium sulfate, the drying agent is:filtered off and the product concentrated. The residue is suspended incold methanol, filtered under suction and dried. Yield 135 g (=74% ofthe theoretical). The liquid crystalline behavior under a polarizationmicroscope is in the range from 190° to 290° C.

EXAMPLE 2 1-(4-methoxyphenyloxycarbonyl)-4-(methoxybenzoyloxy)-benzene##STR76## was prepared in accordance with Example 1b) from the knownp-methoxyphenyl ester of 4-hydroxybenzoic acid (cf. J. P. van Meten, B.H. Klanderman, Mol Cryst., Liquid Cryst. 1973, Vol. 22, pages 285 etseq.) and p-methoxybenzoic acid chloride Yield: 142 g (94% of thetheoretical).

The presence of a liquid crystalline phase was confirmed by polarizationmicroscope in the temperature range from 150° to 300° C.

EXAMPLE 3

1-(4-methoxyphenyloxycarbonyl)-4-(4-methylbenzoyloxy)-benzene.4-Methoxyphenyl-4-hydroxybenzoate was reacted with 4-methylbenzoic acidchloride as in Example 1b. . Yield: 11 g (91% of the theoretical).Liquid crystalline behavior was observed under a polarization microscopein the temperature range from 180° to 330° C.

EXAMPLE 4

1-(4-methylphenyloxycarbonyl)-4-(4-methoxybenzoyloxy)-benzene isprepared as in Example lb from 4-methylphenyl-4-hydroxybenzoate and4-methoxybenzoyl chloride. Yield: 128 g. Liquid crystalline behavior wasobserved in the temperature range from 180° to 330° C.

EXAMPLE 5

4-Benzoyloxybenzoic acid-4-benzoyloxyphenyl ester is prepared as inExample lb from 4-hydroxyphenyl-4-hydroxybenzoate and benzoic acidchloride. Yield: 530 g (80% of the theoretical). A liquid-crystallinephase was observed under a polarization microscope in the temperaturerange from 190° to 350° C.

EXAMPLE 6 4-(4-methylbenzoyloxy)-benzoicacid-4-4-methylbenzoyloxy)phenylester

345.3 g 4-hydroxyphenyl-4-hydroxybenzoate are suspended with 249 gpyridine in 3000 ml methylene chloride and 460 g methylbenzoic acidchloride are added to the resulting suspension over a period of 3 h atT=° C. The reaction mixture is stirred for 14 h at room temperature. Thesolvent is distilled off in vacuo and the residue stirred up with 1.4 15% hydrochloric acid. The insoluble product is filtered under suction,washed with water until neutral and dried. Yield: 643 g (85% of thetheoretical). A liquid crystalline phase is observed under apolarization microscope in the temperature range from I90 to 350 C.

EXAMPLE 7

4-(4-methoxybenzoyloxy)-benzoic acid-4-(4-methoxybenzoyloxy)-phenylester is prepared as in Example 5 from 4-hydroxyphenyl-4-hydroxybenzoateand 4-methoxybenzoic acid chloride. Yield: 420 g (84% of thetheoretical). The presence of a liquid crystalline phase is confirmed bypolarization microscope in the temperature range from 180° to 330° C.

EXAMPLE 8

4-(4-trifluoromethylbenzoyloxy)-benzoicacid-4-(4-trifluoromethylbenzoyloxy)-phenyl ester is prepared as inExample 6 from 4-hydroxyphenyl-4-hydroxybenzoate and4-trifluoromethylbenzoyl chloride. Yield: 12.9 g (80% of thetheoretical). A liquid crystalline phase was observed under apolarization microscope in the temperature range from 180° to 340° C.

EXAMPLE 9

4-(4-chlorobenzoyloxy)-benzoic acid-4-(4-chlorobenzoyloxy)-phenyl esteris prepared as in Example 5 from 4-hydroxyphenyl-4-hydroxybenzoate andp-chlorobenzoic acid chloride. Yield: 250 g (98% of the theoretical). Aliquid crystalline phase is observed under a polarization microscope inthe temperature range from 160° to 350° C.

EXAMPLE 10

4,4'-bis-(phenyloxycarbonyl)-diphenylteraphthalate is prepared as inExample 6 from phenyl-4-hydroxybenzoate and terephthalic aciddichloride. Yield: 140 g (=75% of the theoretical).

EXAMPLE 11

4,4'-bis-(4-methylphenyloxycarbonyl)-diphenyl terephthalate is preparedas in Example 1/5 from 4-methylphenyl-4-hydroxybenzoate and terephthalicacid dichloride. Yield:

EXAMPLE 12

4,4'-bis-(4-methoxyphenyloxycarbonyl)-diphenyl terephthalate is producedas in Example 1/5 from 4-methoxyphenyl-4-hydroxybenzoate andterephthalic acid dichloride. Yield:

EXAMPLE 13

4,4'-bis-(benzoyloxy)-diphenyl terephthalate is produced as in Example 6from 4-hydroxyphenylbenzoate and terephthalic acid dichloride. Yield: 80g (=84% of the theoretical).

EXAMPLE 14

4,4'-bis-(4-methylbenzoyloxy)-diphenyl terephthalate is produced as inExample 6 from 4-hydroxyphenyl-4-methyl-benzoate and terephthalic aciddichloride. Yield: 73 g (=87% of the theoretical).

EXAMPLE 15

4,4'-bis-(4-methoxybenzoyloxy)-diphenyl terephthalate is produced as inExample 1/5 from 4-hydroxyphenyl-4-methoxybenzoate. Yield: 95 g (=88% ofthe theoretical).

EXAMPLE 16

4-Hydroxyphenyl-4-(4-methylbenzoyloxy)-benzoate is reacted as in Example6 with terephthalic acid dichloride. Yield: 45 g (=65% of thetheoretical).

1,4-bis-[[(4-methylbenzoyloxy)-4-benzoyloxy]-4-phenyloxy-carbonyl]-benzene

                  TABLE 1                                                         ______________________________________                                                      Pol. microscope                                                                           DSC                                                 Product       Mp. °C.                                                                            T.sub.u °C.                                  ______________________________________                                         1            195-285     198-291                                              3            135-295     141-305                                              6            194-300     201-280                                             11            165-270     169-278                                             12            250-325     249-330                                             15            230-315     232-310                                             ______________________________________                                    

II. Production of the thermoplastic molding compounds

The thermoplastic molding compounds are produced by two methods:

a) addition of the liquid crystalline compound to the polymer solutionbefore working up and

b) compounding of the amorphous, aromatic polyesters, polyestercarbonates and polycarbonates with the liquid crystalline compounds inthe melt.

The materials used in the Examples and Comparison Examples are describedin the following.

The relative solution viscosities shown were measured in methylenechloride at 25.C for a polymer concentration of 5 g/1.

1. Polycarbonate (PC) of bisphenol A, relative solution viscosityη_(rel) =1.280.

2 Polyester carbonate (APEC) of bisphenol A, ester content 80% byweight, and equimolar quantities of iso- and terephthalic acid preparedin accordance with EP 0 036 080, relative solution viscosity η_(rel)1.294.

3. Polyester (APE) of bisphenol A and equimolar quantities of iso- andterephthalic acid prepared in accordance with DOS 2 940 024, relativesolution viscosity η_(rel) =1.267.

Impact strength a_(n) and notched impact strength a_(k) were tested on80×10×4 mm test specimens in accordance with DIN 53 453 (ISO/R 179) at23° C. using 10 test specimens for each test.

Flexural strength was determined on 80×10×4 mm test specimens inaccordance with DIN 53 452 (ISO/R 178). The elasticity modulus intension was determined in accordance DIN 53 547.

Tensile strength was determined on so-called dumbbell-shaped testspecimens (0.7-fold) in accordance with DIN 53 455. The elasticitymodulus in tension was determined in accordance with DIN 53 457. Meltflow behavior was evaluated by measurement of melt viscosity. Unlessotherwise indicated, the nozzle had a length-to-thickness ratio (L:D) of30:1.

The composition and properties of the thermoplastic molding compoundsare shown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________    Thermoplastic molding compounds based on the polycarbonate Makrolon 2800      Composition                                                                   PC                                                                            2800                                                                             LC-comp. Prod.                                                                             Melt viscosity a.sub.n                                                                            δ.sub.R                                                                     ε.sub.R                                                                  E-M-T                                                                             δ.sub.B                                                                      ε.sub.B                                                                     E-M-B               (%)                                                                              Ex.   (%)                                                                              method                                                                            T = 33° C.; -1000s.sup.-1                                                         T.sub.proc.                                                                       (kJ/m.sup.2)                                                                       (MPa)                                                                             (%)                                                                              (MPa)                                                                             (MPa)                                                                              (MPa) (MPa)               __________________________________________________________________________    100                                                                              --    0  a   320        300 u.b. 65  80 2400                                                                               95  7.4   2200                100                                                                              --    0  b   300        320 u.b. 64  80 2570                                                                               98  7.2   2300                95 1     5  a   80         260 7 × u.b.                                                                     67  65 2940                                                                              120  6.8   2710                                               3 × 130                                  95 1     5  b   75         260 8 × u.b.                                                                     65  65 2960                                                                              118  6.9   2740                                               2 × 140                                  90 1     10 a   40         240 50   70  45 3300                                                                              123  5.3   2980                90 1     10 b   35         240 57   71  45 3310                                                                              121  5.4   2990                95 3     5  b   120        260 9 × u.b.                                                                     72  60 3010                                                                              115  7.1   2720                                               1 × 130                                  95 6     5  b   230        280 9 × u.b.                                                                     66  80 2770                                                                              105  7.3   2530                                               1 × 132                                  95 6     10 b   60         280 8 × u.b.                                                                     59  80 2940                                                                              111  7.0   2740                                               2 × 100                                  95 15    5  b   50         260 9 × u.b.                                                                     70  60 3050                                                                              122  7.0   2730                __________________________________________________________________________     T.sub.proc. : processing temperature                                          a.sub.n : impact strength                                                     δ.sub.R : ultimate tensile strength                                     ε.sub.R : elongation at break                                         EM-T: elasticity modulus in tension                                           δ.sub.B : flexural strength                                             ε.sub.B : outer fiber strain                                          EM-B: elasticity modulus in bending                                      

We claim:
 1. The thermoplastic aromatic polycarbonates, aromaticpolyester carbonates, aromatic polyesters or mixtures, characterized inthat they contain the compounds corresponding to formula (I) inquantities of from 1% by weight, wherein formula (I) is ##STR77## inwhich --Ar is an aromatic group which is mononuclear or polynuclear; thepolynuclear radical being attached by one bond or annellateR¹ and R² isthe same or different and represent a group corresponding to formula (I)a) to 1) below: ##STR78## wherein X represents a substituent selectedfrom the group consisting of H, chlorine, O--C₁₋₄ alkyl, C₃₋₆-cycloalkyl, O--C₆₋₁₄ aryl, C₁₋₄ -alkyl, C₃₋₆ -cycloalkyl, C₆₋₁₄ -aryl,fluorinated C₁₋₄ -alkyl, fluorinated C₃₋₆ -cycloalkyl and fluorinatedC₆₋₁₄ -aryl, --M¹ and --M² is the same or different and represent groupswith two bonds corresponding to formula ##STR79## and m is1 or 2, n is 1or 2, o is 1 or 2 and p is
 1. 2. Thermoplastic aromatic polycarbonates,aromatic polyester carbonates, aromatic polyesters or mixtures accordingto claim 1 wherein for formula (I), --Ar-- is ##STR80##
 3. Thermoplasticaromatic polycarbonates, aromatic polyester carbonates, aromaticpolyesters or mixtures according to claim 1 wherein M₁ and M₂ are##STR81## .